# connected.lpp: Connected Components of a Point Pattern on a Linear Network In spatstat.linnet: Linear Networks Functionality of the 'spatstat' Family

 connected.lpp R Documentation

## Connected Components of a Point Pattern on a Linear Network

### Description

Finds the topologically-connected components of a point pattern on a linear network, when all pairs of points closer than a threshold distance are joined.

### Usage

```## S3 method for class 'lpp'
connected(X, R=Inf, ..., dismantle=TRUE)
```

### Arguments

 `X` A linear network (object of class `"lpp"`). `R` Threshold distance. Pairs of points will be joined together if they are closer than `R` units apart, measured by the shortest path in the network. The default `R=Inf` implies that points will be joined together if they are mutually connected by any path in the network. `dismantle` Logical. If `TRUE` (the default), the network itself will be divided into its path-connected components using `connected.linnet`. `...` Ignored.

### Details

The function `connected` is generic. This is the method for point patterns on a linear network (objects of class `"lpp"`). It divides the point pattern `X` into one or more groups of points.

If `R=Inf` (the default), then `X` is divided into groups such that any pair of points in the same group can be joined by a path in the network.

If `R` is a finite number, then two points of `X` are declared to be R-close if they lie closer than `R` units apart, measured by the length of the shortest path in the network. Two points are R-connected if they can be reached by a series of steps between R-close pairs of points of `X`. Then `X` is divided into groups such that any pair of points in the same group is R-connected.

If `dismantle=TRUE` (the default) the algorithm first checks whether the network is connected (i.e. whether any pair of vertices can be joined by a path in the network), and if not, the network is decomposed into its connected components.

### Value

A point pattern (of class `"lpp"`) with marks indicating the grouping, or a list of such point patterns.

### Author(s)

.

`thinNetwork`

### Examples

```   ## behaviour like connected.ppp
U <- runiflpp(20, simplenet)
plot(connected(U, 0.15, dismantle=FALSE))

## behaviour like connected.owin
## remove some edges from a network to make it disconnected
plot(simplenet, col="grey", main="", lty=2)
A <- thinNetwork(simplenet, retainedges=-c(3,5))